The core method of converting PHP arrays into query strings is to use the http_build_query function, which can automatically handle nested arrays and encoding problems; for simple structures, you can also manually splice them, but you need to pay attention to rawurlencode and ending symbol processing; in addition, characters such as spaces, Chinese and other characters in the parameters will be encoded, and the front and back ends need to uniform encoding specifications to avoid parsing errors. The specific steps are as follows: 1. It is recommended to use the built-in function http_build_query, which will automatically encode the key value and retain the index; 2. For simple arrays, you can manually traverse the splicing, but it needs to be used with rawurlencode; 3. Pay attention to the consistency of special characters in the query string, and you can use parse_str for reverse parsing.

It is actually quite common to convert PHP arrays into query strings, especially when doing URL parameter splicing or API requests. The key is how to deal with various types of array structures, ensuring that the output format is standard key=value & stitching.

Using http_build_query is the most direct way

The http_build_query function that comes with PHP is specifically used to do this. It can automatically handle array nesting, encode special characters, and is also compatible with GET and POST request requirements.

For example:

 $data = [
    'name' => 'John Doe',
    'age' => 30,
    'hobbies' => ['reading', 'coding']
];

echo http_build_query($data);

The output result will be:

 name=John Doe&age=30&hobbies[0]=reading&hobbies[1]=coding

As you can see, the keys in the array will be automatically encoded, the spaces will become plus signs, and the index will be retained. If you want to make nested arrays become more friendly (such as without indexes), you have to deal with the array structure yourself.

Manual splicing is suitable for simple situations

If you just want to quickly spell a simple query string, you can also do it manually:

 $data = [
    'page' => 2,
    'sort' => 'desc'
];

$query = '';
foreach ($data as $key => $value) {
    $query .= $key . '=' . rawurlencode($value) . '&';
}
echo rtrim($query, '&');

Output:

 page=2&sort=desc

This method is suitable for situations where the data structure is particularly simple, but when encountering multi-dimensional arrays or special characters, it is easy to have problems, which is not as stable as http_build_query .

Pay attention to encoding and decoding issues

When generating a query string, the spaces, Chinese, and symbols in the parameter value will be encoded, such as the space becomes or , Chinese becomes the %xx%xx form encoded by UTF-8.

Conversely, if you want to restore the query string to an array, you can use parse_str :

 parse_str('name=John Doe&age=30', $output);
print_r($output);

Output:

 Array
(
    [name] => John Doe
    [age] => 30
)

Therefore, you should pay attention to whether the encoding processing between the two sides is consistent during the interaction between the front and back ends, otherwise the problem of not being able to retrieve the parameters will occur.

Basically that's it. It is most convenient to use http_build_query , manual splicing is also OK, but you have to pay attention to the details. If the array structure is complex, it is best to process it in advance and then transfer it to avoid unexpected field names or indexes.

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